Torque power wrench marking device

ABSTRACT

A fluid actuated torque power wrench that includes a power driven member for rotating a fastener to a desired degree of torque and automatically discharging a predetermined quantity of colored ink or paint on the fastener after the completion of the torquing operation. The spot of ink or paint on a fastener immediately indicates to an inspector that the fastener has been torqued to a predetermined degree.

United States Patent Palmer et al.

[ 51 Sept. 26, 1972 [54] TORQUE POWER WRENCH MARKING DEVICE [72] Inventors: Oakley Butler Palmer, 12852 Lakewood Blvd., Downey, Calif. 90241; Paul E. Spencer, 513 S. Dale St., Anaheim, Calif. 92804 221 Filed: April2l, 1971 211 Appl. No.: 133,225

[52] US. Cl ..8l/52.4, 173/12 [51] Int. Cl ..B25b 23/14, B25b 21/00 [58] Field of Search ..81/52.4, 52.5, 53 R; 173/12;

[56] References Cited UNITED STATES PATENTS Dunham ..-.....81/53 R 11/1961 Hines et a1. ..8l/52.5 X Lance ..81/52.5

Primary Examiner-Robert C. Riordon Assistant Examiner-Roscoe V. Parker, Jr. Attorney-William C. Babcock [5 7] ABSTRACT A fluid actuated torque power wrench that includes a power driven member for rotating a fastener to a desired degree of torque and automatically discharging a predetermined quantity of colored ink or paint on the fastener after the completion of the torquing operation. The spot of ink or paint on a fastener immediately indicates to an inspector that the fastener has been torqued to a predetermined degree.

6 Claims, 7 Drawing Figures TORQUE POWER WRENCH MARKING DEVICE BACKGROUND OF THE INVENTION 1 Field of the Invention A torque power wrench marking device.

2. Description of the Prior Art During the past few years fluid actuated torque wrenches have been developed for tightening fasteners such as nuts, bolts and the like to a predetermined degree of torque. Although such wrenches have been available, there has been no easy and convenient way for inspectors to determine whether a mechanic or workman using the wrench has tightened a fastener to a desired degree of torque. Fasteners as used in modern industry are designed to be torqued within a relatively narrow critical range to provide optimum results and either overtorquing or undertorquing of the fastener detracts from the fastener providing maximum holding qualities.

The primary purpose in devising the present invention is to supply a power driven torque wrench that automatically ceases to rotate a nut, bolt or other fastener after a desired degree of torque has been exerted thereon, and the tool in addition serving to indicate by visual means, such as a spot of ink or paint discharged onto the fastener, that the fastener has been torqued to a predetermined degree.

SUMMARY OF THE INVENTION A fluid actuated torque wrench that includes a power driven rotatable member for tightening a fastener such as a bolt or nut with a desired degree of torque, and the rotatable member not only serving this function, but serving as a guide for a tube through which an identifying glob of colored ink or paint is discharged onto the fastener after the torque operation is completed.

A major object of the present invention is to supply a fluid actuated torque wrench for rotating a fastener such as a bolt or nut until a desired degree of torque is exerted thereon, and at the conclusion of the torquing operation discharging a glob of paint or ink onto the fastener to indicate that the fastener has been tightened with a predetermined degree of torque exerted thereon.

Another object of the invention is to supply a fluid actuated torque wrench of relatively simple mechanical structure that automatically identifies a fastener that has been rotated to a desired degree of torque by the fastener having a spot of ink or paint discharged thereon, with the wrench achieving these two objectives automatically, and as a result capable of being used by persons having relatively little mechanical skill.

A still further object of the invention is to supply a combined torque wrench and marking device that has a relatively simple mechanical structure, can .be fabricated from standard commercially available materials, requires a minimum of maintenance attention, is relatively inexpensive to manufacture, and can accordingly be retailed at a relatively low price to those companies and corporations that require precision tightening of fasteners.

BRIEF DESCRIPTION OF THE DRAWING HO. 1 is a side elevational view of a combined torque wrench and marking device;

FIG. 2 is a fragmentary combined side elevational and cross sectional view of a forward portion of the wrench, and this portion removably engaging a socket for tightening a nut;

FIG. 3 is a top plan view of a bolt supported nut that has been torqued to a desired degree, and is identified by a colored area of paint or ink that is discharged onto the threaded member after the torquing of the nut is completed;

FIG. 4 is a fragmentary longitudinal cross sectional view of a portion of the first form of the device taken on the line 4-4 of FIG. 1;

FIG. 5 is an enlarged fragmentary longitudinal cross sectional view of one of the couplings that removably connects a tube associated with the wrench;

FIG. 6 is a transverse cross sectional view of the coupling shown in FIG. 5 taken on the line 6-6 thereof; and

FIG. 7 is a diagrammatic view of a second form of the torque wrench and the fluid actuated assembly associated therewith for automatically torquing and identifying rotatable fastener.

DESCRIPTION OF THE PREFERRED EMBODIMENT A first form of the combined torque wrench and marking device A is shown in FIG. 1 and includes a longitudinally apertured power driven rotatable member B of non-circular transverse cross section that is adapted to removably engage a socket C as shown in FIG. 2. The socket C is adapted to engage a nut 10 to tighten the same with a desired degree of torque on a threaded rod 12 that extends upwardly from a workpiece 14.

A tubular conduit D is provided that is connected to a source of fluid under pressure, and is connected with a hydraulic motor (not shown) situated within the confines of the wrench A, and this motor by gearing (not shown) driving the rotatable member B. Flow of fluid from the line D to the motor (not shown) is controlled by a handle 16 of a valve (not shown). The handle 16 due to spring means 18 or other conventional means is normally in a position to close the valve associated therewith to prevent the flow of fluid under pressure to the motor (not shown).

A receptacle E is provided that is convenientlyin the form of a hollow box that has an identifying liquidholding container F situated therein. The container F supplies the identifying liquid to a fluid actuated pump G, which pump may conveniently be of the structure described in the Warren J. Walsh U.S.- Pat. No. 3,599,753 on a Conveyor Roller Lubricating Device.

The member B is rotatably supported in a head 20 that forms a part of the torque wrench A. A first band 22 encircles the body of the wrench A adjacent the head 20 and serves to support an elongate member 24 shown in detail in FIG. 4 that has a longitudinal bore 26 therein. A tubular member 28 is normally disposed to the member 24, and secured thereto by conventional means. Tubular member 28 is in communication with bore 26. The end portion of the member 24 adjacent tubular member 28 has internal threads 30 formed thereon that are engaged by a threaded plug 32. Tubular member 24 extends through a longitudinal bore 29 in rotatable member B. The member B may rotate relative to tubular member 24.

The member 24 at a second end 34 thereof is connected to a first tube 36 that is held in a fixed position on the torque wrench A by a second band 38. The first tube 36 as may be seen in FIGS. 1 and terminates in a coupling H. The first tube 36 has a second tube 40 of substantially smaller diameter situated in the interior thereof and this second tube extending into the bore 26 of member 24 as shown in FIG. 4.

The second tube 40 supports an orifice defining member 42 on the left hand end thereof as viewed in FIG. 4 that is situated adjacent the tubular member 28.

The coupling H as may best be seen in FIG. 5 includes two cylindrical bodies 44 and 44' that have longitudinal coaxially aligned bores 46 and 46 formed therein. The bodies 44 and 44 have adjacent end portions 48 and 48 that engage an opening 50 that extends longitudinally through body 52.

The bodies 44 and 44' are removably held in coaxially aligned positions as shown in FIG. 5 by two rigid U- shaped members 54 and 54 that engage transversely aligned slots 56 and 56 formed in the bodies 44 and 44 and slots 58 and 58 formed in the body 52. The resilient O-rings 60 and 60' are provided that are mounted on the bodies 44 and 44 and are in sealing engagement with the body 52.

The first tube 36 has a flanged end 62 that is held in sealing engagement with the left hand end portion of the body 44 as viewed in FIG. 5 by an internally threaded cap 64 that engages external threads 66 formed on the body 44. Extensions 36 and 40 of the tubes 36 and 40 extend from the right of the coupling as viewed in FIG. 5 as well as in FIG. 1, and are of the same structure and dimensions as the tubes 36 and 40.

Adjacent ends of the second tubes 40 and 40 are connected by tubular inserts 68 and 68'. The first tube extension 36 is secured to the body 62 by a cap 64 that is of the same structure as the cap 64. The first tube 36 and second tube 40 cooperate to define a longitudinal annulus-shaped confined space 41 that is in communication with a like annulus-shaped space 41 defined by the extensions 36 and 40. By removing the U-shaped members 54 and 54, the bodies 44 and 44 may be easily separated from one another to clean or service the tubular inserts 68 and 68'. The inserts 68 and 68 as may best be seen in FIG. 6 have cylindrical end portions that engage the second tubes 40 and 40, but with adjacent portions of the inserts interlocking with one another and being of substantially square transverse cross section.

The first tube extension 36' as can best be seen in FIG. 1 continues to a T-fitting 70, which fitting has a second tube extension 72 connected thereto that is in communication with the first tube extension 40 and is also connected to a check valve 74. The check valve 74 is connected to an identifying liquid discharge line 76 that is in communication with the interior of the pump G. The container F has the discharge for the identifying liquid therein connected to a check valve 77 that by conventional tube fittings 78 is connected to the interior of the pump G.

The receptacle E has a ring 80 or other supporting means secured thereto, and this supporting means being used to maintain the receptacle at a position (not shown) that is adjacent to the location where the wrench A will be used. When the receptacle E is so supported by ring 80, liquid in the container F will at all times tend to flow therefrom by gravity, but will normally be blocked from so doing by the check valve 77. The check valve 77 is of such a type that it remains closed except when a piston (not shown) within the confines of the pump G is moved to create a negative pressure within the pump, with the check valve 77 then opening to permit a predetermined quantity of the identifying liquid to be drawn into the pump.

When the direction of movement of the piston (not shown) is towards the check valve 74, the check valve 77 remains closed, and the check valve 74 opens to permit a predetermined quantity of the identifying liquid to be discharged into the tee 70. The tee is connected by a tubular member 81 to the interior of a second tee 82, and the connection 81 serving to effect communication between the interior of the tee 82 and the annulus-shaped space 41' defined between the first and second tube extension 36 and 40 as shown in FIG. 5. The tee 82 is connected to a third tube 84 that extends to a coupling H, and the coupling I-I' having a fourth tube 86 extending therefrom to a valve 88 that is mounted on the body of the wrench A as shown in FIG. 1.

The valve 88 is in communication with the fluid actuating the motor (not shown) that drives the member B, and is located downstream from the valve (not shown) that is actuated by the handle 16. The valve 88 is spring loaded and normally is in a closed position.

Fluid under pressure is delivered through the conduit D to drive the rotatable member B to tighten a nut 10 as shown in FIG. 2. Upon a desired torque having been placed on the nut 10 due to the force exerted by the fluid flowing through the conduit D to the driving motor (not shown) the valve 88 moves to a second position due to build up of fluid pressure in the wrench A, with the valve venting this excess pressure to the ambient atmosphere, as well as through the fourth tube 86, coupling I-I, third tube 84, tee 82, and fifth tube 90 to the interior of the pump G as shown in FIG. 1. As fluid under pressure flows through the fifth tube 90 into the pump G, the piston is moved longitudinally therein, to discharge a glob of the identifying liquid through the check valve 74, tube 72, tee 70, second tube extension 40', second tube 40, and orifice defining member 42. Concurrently, fluid under pressure flows from the tee 82, connection 81 and annulus-shaped spaces 41 and 41 to discharge about the extremity of the orifice defining member 42, to entrain a glob of the identifying liquid therewith and carry the same downwardly through the tubular member 28 to deposit the glob on the upper end of the tubular member 12 where it defines a colored area 94. As soon as air starts to be vented from the wrench A as above described, the user releases the handle 16, and the torquing and marking identifying operation is completed for that particular fastener. The movable piston in the pump G is spring loaded, and returns to its initial position, and in so doing draws a quantity of identifying liquid through first check valve 77 and fitting 78 into the confines of the pump, which liquid will be used in the next torquing and marking operation.

An alternate form of the device is shown in FIG. 7 which includes a source 96 of air at substantially constant pressure. Air discharges from the source 96 through a line 98 that is connected to an air filter 100. The air filter 100 is connected to a line 102 that extends to a manually operated valve 104 that is normally closed. The valve 104 is connected to a line 106 that extends to a manifold 108 and the manifold in turn being connected to a coupling 110. Coupling 110 is connected to the interior of the wrench A to supply air under pressure to the motor (not shown) therein.

Line 102 is connected to a lateral 112 that divides into first and second line 114 and 116. Line 114 is connected to a pressure regulator 118 that has a line 120 extending therefrom to a sensing valve 122. The line 116 is connected to the sensing valve 122, and is in communication with a line 124 when the sensing valve 122 is actuated to move from a normally closed position to an open position. Manifold 108 is in communication with a tube 126 that extends to a filter 128 and the filter in turn being connected by a line 130 to the sensing valve 122. The balance of the alternate form of the invention is the same as in the first described form.

The at at regulated pressure in the line 120 maintains the sensing valve in a closed position. Upon the user opening the valve 104, air flows to the motor (not shown) in the torque wrench A to rotate the same, as well as member B, and upon the fastener being torqued to a desired degree, fluid pressure immediately starts to build up in the manifold !08, and this increased pressure of fluid in line 106 and line 130 actuating the sensing valve 122 to move to the open position where fluid under pressure flows through the lines 116 and 124 to actuate the pump G in the same manner as in the first described form of the invention. The air under pressure both actuates the pump G and discharges a predetermined quantity of identifying liquid onto the threaded member 12 as previously described.

Both the form of the invention disclosed in FIGS. 1 to 6 inclusive and in FIG. 7 operate in the same manner, and further description of this operation is not required.

To prevent identifying liquid leaking from the orifice defining member 42 when the device is not actuated, a resilient member 150 is slidably supported in a cavity 152 formed in the plug 32. The member 150 is at all times urged into pressure contact with member 42 by a compressed helical spring 154 as shown in FIG. 4. When identifying liquid in second tubular member 40, which tubular member is at all times filled with the liquid, is subjected to increased pressure, a predetermined quantity of the liquid is discharged from the orifice defining member 42 and is blown down the tubular member 28 by air in atomized form for marking purposes.

We claim:

1. In combination with a power operated wrench of the type that includes an elongate body that houses an air operated motor that drives a rotatable first elongate member capable of rotating a fastener until a desired torque is placed on the latter, said motor being supplied with air under pressure through a conduit that extends outwardly from said body, with the flow of air from said conduit to said motor controlled by a first manually operated valve, an assembly for discharging a predetermined quantity of a colored identifying liquid onto said fastener after said torquing is completed, said assembly including:

a. an identifying liquid holding container;

b. an air operated pump of the type that includes a liquid inlet and liquid discharge outlet and an opening through which pressurized air is discharged into said pump to actuate the latter, with said pump each time it is pressurized with air discharging a predetermined quantity of liquid from said outlet and drawing a like quantity of liquid into said pump through said inlet;

c. first tube means connecting said inlet to the interior of said container;

. a tubular member that extends through a longitudinal bore in said first elongate member, said first elongate member rotatable relative to said tubular member;

e. a second elongate member having a longitudinal bore therein, said first elongate member secured to said second elongate member and in communication with said bore;

f. a first flexible tube and a second flexible tube of smaller diameter disposed therein that cooperate to define a longitudinal space of annulus-shaped space therebetween, said first and second tubes extending into said bore to terminate adjacent said tubular member, said second tube connected to said discharge outlet of said pump;

g. a second normally closed spring loaded valve mounted on said body and in communication with the air supply to said motor downstream from said first valve, said valve opening to permit air to discharge from said motor through an opening in said second valve when the pressure on said air exceeds that pressure at which said fastener has been torqued to a desired degree;

h. a third flexible tube connecting said opening in said second valve to said opening in said pump to actuate the latter to discharge said predetermined quantity of said identifying liquid into said second tube that is already filled with said liquid, and a predetermined quantity of said liquid being displaced from said second tube adjacent said tubular member; and

i. first tubular means that maintain communication between said third tube and said annulus-shaped space for air to discharge through the latter when said second valve opens to subsequently flow from said first tubular member to deposit said displaced predetermined quantity of identifying liquid on said fastener.

2. The combination as defined in claim 1 which in addition includes:

j. an orifice defining member disposed in said bore adjacent said tubular member and connected to said second tube for preventing discharge of said identifying liquid therefrom except when said pump is actuated.

3. The combination as defined in claim 1 in which said conduit is removably connected to said body and said combination in addition including:

j. first and second coupling means in said first and second tubes and said third tube respectively, adjacent said body to permit said body to be separated from said first and second tubes and said third tube when said body is separated from said conduit.

4. The combination as defined in claim 1 in which said first tubular means includes:

j. a first tubular tee that has first, second and third openings therein that is interposed in said first and second tubes intermediate said pump and said body, with said second tube entering said tee at said first opening and emerging therefrom at said second opening and cooperating with the interior of said tee to define a continuation of said annulusshaped space;

k. second tubular means connecting said third opening to the interior of said third tube; and

1. means for preventing air discharged into said continuation of said annulus-shaped space venting to the ambient atmosphere through said second opening.

5. The combination as defined in claim 4 in which said second tubular means includes:

m. a second tubular tee having first, second and third openings, said second tee interposed in said third tube and having said first and second openings connected thereto; and

n. third tubular means connecting said third openings in said first and second tees to one another.

6. In combination with a power operated wrench of the type that includes an elongate body that houses an air operated motor that drives a rotatable first elongate member capable of rotating a fastener until a desired torque is placed on the latter, an assembly for discharging a predetermined quantity of a colored identifying liquid onto said fastener after said torquing has been completed by pressurized air discharged to said air motor through an opening in said body from a source of said air, said assembly including:

a. an identifying liquid holding container;

b. an air operated pump of the type that includes a liquid inlet and liquid discharge outlet and an opening through which pressurized air is discharged into said pump to actuate the latter, with said pump each time it is pressurized with air discharging a predetermined quantity of liquid from said outlet and drawing a like quantity of liquid into said pump through said inlet;

c. first tube means connecting said inlet to the interior of said container;

d. a sensing valve having first, second, third and fourth openings therein, said sensing valve when air at a pressure that is less than that at said source is supplied to said second opening being in a first position where communication between said first and fourth openings is obstructed, and said sensing valve when air is supplied to said third opening assuming a second position where air may flow from said first to said fourth opening;

e. a tubular member that extends through a longitudinal bore in said first elongate member, said first elongate member rotatable relative to said tubular member;

f. a second elongate member having a longitudinal bore therein, said first elongate member secured to said second elongate member and in communication with said bore;

g. a first flexible tube and a second flexible tube of smaller diameter disposed therein that cooperate to define a longitudinal space of annulus-shaped space therebetween, said first and second tubes extending into said bore to terminate adjacent said tubular member, said second tube connected to said discharge outlet of said pump;

h. a pressure reducing valve having an inlet and an outlet;

i. second tube means in communication with said source of air, said opening in said body, said inlet in said pressure reducing valve, and said first opening in said sensing valve;

j. a normally closed manually operated valve in said first tube means for controlling flow of said pressurized air to said opening in said body;

k. third tube means connecting said third opening in said sensing valve to said first tube means downstream from said valve therein; and

l. fourth tube means connecting said fourth opening in said sensing valve to said opening in said pump and to said annulus-shaped space, with an increase in air pressure in said third tube means causing said sensing valve to move to said second position to allow air from said sensing valve to actuate said pump to discharge a predetermined quantity of said identifying liquid on said fastener after the latter has been torqued to a desired degree and the pressure on air in said second tube means exceeds that of said reduced air pressure in said second opening. 

1. In combination with a power operated wrench of the type that includes an elongate body that houses an air operated motor that drives a rotatable first elongate member capable of rotating a fastener until a desired torque is placed on the latter, said motor being supplied with air under pressure through a conduit that extends outwardly from said body, with the flow of air from said conduit to said motor controlled by a first manually operated valve, an assembly for discharging a predetermined quantity of a colored identifying liquid onto said fastener after said torquing is completed, said assembly including: a. an identifying liquid holding container; b. an air operated pump of the type that includes a liquid inlet and liquid discharge outlet and an opening through which pressurized air is discharged into said pump to actuate the latter, with said pump each time it is pressurized with air discharging a predetermined quantity of liquid from said outlet and drawing a like quantity of liquid into said pump through said inlet; c. first tube means connecting said inlet to the interior of said container; d. a tubular member that extends through a longitudinal bore in said first elongate member, said first elongate member rotatable relative to said tubular member; e. a second elongate member having a longitudinal bore therein, said first elongate member secured to said second elongate member and in communication with said bore; f. a first flexible tube and a second flexible tube of smaller diameter disposed therein that cooperate to define a longitudinal space of annulus-shaped space therebetween, said first and second tubes extending into said bore to terminate adjacent said tubular member, said second tube connected to said discharge outlet of said pump; g. a second normally closed spring loaded valve mounted on said body and in communication with the air supply to said motor downstream from said first valve, said valve opening to permit air to discharge from said motor through an opening in said second valve when the pressure on said air exceeds that pressure at which said fastener has been torqued to a desired degree; h. a third flexible tube connecting said opening in said second valve to said opening in said pump to actuate the latter to discharge said predetermined quantity of said identifying liquid into said second tube that is already filled with said liquid, and a predetermined quantity of said liquid being displaced from said second tube adjacent said tubular member; and i. first tubular means that maintain communication between said third tube and said annulus-shaped space for air to discharge through the latter when said second valve opens to subsequently flow from said first tubular member to deposit said displaced predetermined quantity of identifying liquid on said fastener.
 2. The combination as defined in claim 1 which in addition includes: j. an orifice defining member disposed in said bore adjacent said tubular member and connected to said second tube for preventing discharge of said Identifying liquid therefrom except when said pump is actuated.
 3. The combination as defined in claim 1 in which said conduit is removably connected to said body and said combination in addition including: j. first and second coupling means in said first and second tubes and said third tube respectively, adjacent said body to permit said body to be separated from said first and second tubes and said third tube when said body is separated from said conduit.
 4. The combination as defined in claim 1 in which said first tubular means includes: j. a first tubular tee that has first, second and third openings therein that is interposed in said first and second tubes intermediate said pump and said body, with said second tube entering said tee at said first opening and emerging therefrom at said second opening and cooperating with the interior of said tee to define a continuation of said annulus-shaped space; k. second tubular means connecting said third opening to the interior of said third tube; and l. means for preventing air discharged into said continuation of said annulus-shaped space venting to the ambient atmosphere through said second opening.
 5. The combination as defined in claim 4 in which said second tubular means includes: m. a second tubular tee having first, second and third openings, said second tee interposed in said third tube and having said first and second openings connected thereto; and n. third tubular means connecting said third openings in said first and second tees to one another.
 6. In combination with a power operated wrench of the type that includes an elongate body that houses an air operated motor that drives a rotatable first elongate member capable of rotating a fastener until a desired torque is placed on the latter, an assembly for discharging a predetermined quantity of a colored identifying liquid onto said fastener after said torquing has been completed by pressurized air discharged to said air motor through an opening in said body from a source of said air, said assembly including: a. an identifying liquid holding container; b. an air operated pump of the type that includes a liquid inlet and liquid discharge outlet and an opening through which pressurized air is discharged into said pump to actuate the latter, with said pump each time it is pressurized with air discharging a predetermined quantity of liquid from said outlet and drawing a like quantity of liquid into said pump through said inlet; c. first tube means connecting said inlet to the interior of said container; d. a sensing valve having first, second, third and fourth openings therein, said sensing valve when air at a pressure that is less than that at said source is supplied to said second opening being in a first position where communication between said first and fourth openings is obstructed, and said sensing valve when air is supplied to said third opening assuming a second position where air may flow from said first to said fourth opening; e. a tubular member that extends through a longitudinal bore in said first elongate member, said first elongate member rotatable relative to said tubular member; f. a second elongate member having a longitudinal bore therein, said first elongate member secured to said second elongate member and in communication with said bore; g. a first flexible tube and a second flexible tube of smaller diameter disposed therein that cooperate to define a longitudinal space of annulus-shaped space therebetween, said first and second tubes extending into said bore to terminate adjacent said tubular member, said second tube connected to said discharge outlet of said pump; h. a pressure reducing valve having an inlet and an outlet; i. second tube means in communication with said source of air, said opening in said body, said inlet in said pressure reducing valve, and said first opening in said sensing valve; j. a normally closed manually operated valve in saiD first tube means for controlling flow of said pressurized air to said opening in said body; k. third tube means connecting said third opening in said sensing valve to said first tube means downstream from said valve therein; and l. fourth tube means connecting said fourth opening in said sensing valve to said opening in said pump and to said annulus-shaped space, with an increase in air pressure in said third tube means causing said sensing valve to move to said second position to allow air from said sensing valve to actuate said pump to discharge a predetermined quantity of said identifying liquid on said fastener after the latter has been torqued to a desired degree and the pressure on air in said second tube means exceeds that of said reduced air pressure in said second opening. 